Important Core Java Interview Questions

Core Java is a popular programming language that is widely used for developing enterprise-level applications. If you are planning to appear for a Java developer interview, you must be prepared to answer a wide range of Core Java interview questions. In this blog post, we have compiled a list of some of the most important Core Java interview questions that you should know to increase your chances of getting hired.

  1. What is Java?

Java is a high-level, object-oriented programming language that is designed to run on any platform without the need for recompilation. It was developed by James Gosling at Sun Microsystems in the mid-1990s.

  1. What are the main features of Java?

Java is known for its simplicity, object-orientation, portability, security, and platform independence. These features make it a popular choice for developing enterprise-level applications.

  1. What is the difference between an interface and an abstract class in Java?

An interface is a collection of abstract methods that can be implemented by a class, while an abstract class is a class that cannot be instantiated and can contain both concrete and abstract methods. Additionally, a class can implement multiple interfaces, but can only inherit from one abstract class.

  1. What is the difference between a compiler and an interpreter in Java?

A compiler translates source code into machine code, while an interpreter executes source code line by line. Java uses both a compiler and an interpreter, with the Java compiler translating source code into bytecode and the Java Virtual Machine interpreting the bytecode at runtime.

  1. What is the difference between static and non-static methods in Java?

Static methods belong to the class and can be accessed using the class name, while non-static methods belong to the object and can only be accessed through an instance of the class.

  1. What is the difference between a HashMap and a TreeMap in Java?

A HashMap is an unordered collection that stores key-value pairs and uses hashing to store and retrieve elements, while a TreeMap is an ordered collection that stores key-value pairs and maintains elements in sorted order.

  1. What is the difference between an ArrayList and a LinkedList in Java?

An ArrayList is an ordered collection that allows fast access to elements using an index, while a LinkedList is an ordered collection that allows fast insertion and removal of elements.

  1. What is the difference between method overloading and method overriding in Java?

Method overloading is when a class has multiple methods with the same name but different parameters, while method overriding is when a subclass provides a new implementation of a method that is already defined in its superclass.

  1. What is the difference between a thread and a process in Java?

A process is an instance of a program that is being executed, while a thread is a lightweight unit of execution within a process. Multiple threads can be executed within a single process.

  1. What is the purpose of the Java Virtual Machine?

The Java Virtual Machine is responsible for executing Java bytecode and providing a platform-independent environment for Java programs to run. It also provides memory management and garbage collection

Leave a Reply